1. Field of the Invention
This invention relates generally to sheet registration mechanisms and, more specifically, to a sheet registration mechanism for copier apparatus. The sheet registration mechanism of the invention is used for locating a document sheet on a platen during any one of several possible modes of operation, including feeding of sheets once or twice to a platen for copying one or both sides thereof, in a document positioner mode in which sheets are not recirculated but are fed once to the platen for copying, and in a manual mode of operation wherein the registration mechanism provides an edge for manual alignment of a document sheet on the platen for copying.
2. Description of the Prior Art
Document and copy sheet registration mechanisms are well known in the art. In some instances these mechanisms have been provided in connection with document feeding apparatus so that a document can be fed to the platen of a copier and the registration mechanism will properly position the document on the platen for exposure by the copier. Typical disclosures of this type of apparatus are found in U.S. Pat. Nos. 3,747,918; 3,844,552; 3,910,570 and 3,992,002. It is also known to provide sheet registration mechanisms that pivot between a registration position wherein the mechanism engages a sheet from a position above the surface on which a sheet travels and a second position spaced from the surface to allow passage of the sheet after registration. Typical disclosures of this type of apparatus are found in U.S. Pat. Nos. 986,726; 2,605,103; 2,613,930; 3,006,637; 3,080,163 and 3,173,685.
Some models of the EKTAPRINT Copier/Duplicator (manufactured by the assignee of the present invention) comprise an automatic document feeder generally as shown in British Pat. No. 1,492,466. In these models a registration mechanism is manually moved to a registration position when documents are to be manually placed on the platen for copying. The registration mechanism is manually pivoted away from the platen before the recirculating document feeder is swung to its operative position over the platen. The recirculating feeder includes a pair of registration feet that move downwardly into engagement with the platen for stopping and registering document sheets fed to the platen by the recirculating feeder. Thus two separate registration mechanisms are provided, one for manual feeding and another for automatic feeding of document sheets to the platen. Also one mechanism is located on the copier and the other is located on the feeding mechanism. Operator intervention is required to change from manual to automatic registration modes.
In some instances it is desireable to feed document sheets to the platen from each of two directions as, for example, disclosed in the commonly assigned U.S. patent application Ser. No. 923,874 filed July 12, 1978 in the names of R. Holzhauser et al and entitled SHEET FEEDING APPARATUS FOR USE WITH COPIER/DUPLICATOR OR THE LIKE. Using the apparatus disclosed in that application, document sheets can be fed to the platen first in one direction and then the opposite direction for copying both sides of the document sheets, and sheets are fed to the platen in one direction only for copying only one side of document sheets. When copying simplex (one sided) originals or duplex (two sided) originals, the sheets are registered by a mechanism located in the sheet feeder. When the feeding apparatus is swung out of the way for copying by manually placing a sheet on the platen, the registration mechanism is no longer available for use. Thus a separate manual registration mechanism should be provided and positioned so that it does not interfere with sheets when they are automatically circulated along the various paper paths.
In view of the foregoing it will be seen that it is very desireable to have an automatic sheet registration mechanism which requires no manipulation by an operator in order to change between various modes of operation, including a simplex mode, a duplex mode, a document positioner mode and a manual mode, and also to have such a mechanism fixed on the copier with respect to the platen for ease of alignment.